Encapsulating upper layers of CDMA signaling between a multi-mode device and a signaling gateway

ABSTRACT

Methods and systems are provided for encapsulating upper layers of CDMA signaling messages between a multi-mode device and a signaling gateway. In an exemplary embodiment, a multi-mode device has a CDMA mode and a Wi-Fi mode. In Wi-Fi mode, the device generates an upper-layer portion of a CDMA signaling message. The device then encapsulates the first upper-layer portion in at least one packet-switched-protocol, such as SIP. The device then transmits the encapsulated upper-layer portion of the CDMA signaling message via a Wi-Fi network and a packet-switched network to a signaling gateway, which then translates the upper-layer portion into an SS7 message, and transmits the SS7 message over an SS7 network.

BACKGROUND

1. Technical Field

The present invention relates to wireless communications and, moreparticularly, to methods and systems for serving multi-modecommunication devices.

2. Description of Related Art

In a cellular wireless communication system, a mobile stationcommunicates over the air with a Radio Access Network (RAN) according toan air interface protocol such as Code Division Multiple Access (CDMA),perhaps in conformance with one or more specifications such as IS-95 andIS-2000. The RAN in turn provides connectivity with one or moretransport networks, such as the public switched telephone network (PSTN)and the Internet. To handle call setup, teardown, handoffs, and otherfunctions, the mobile station and the RAN exchange CDMA signalingmessages, such as IS-2000 signaling messages. Typically, the RAN isconnected with a Mobile Switching Center (MSC), which in turn isconnected with a signaling network such as a Signaling System 7 (SS7)network, over which the MSC signals with other switching points toperform call processing on behalf of the mobile station.

To place a call over the PSTN, for instance, the mobile station would,using IS-2000 as an exemplary CDMA protocol, send an IS-2000 originationmessage over the air to the RAN. That message or an equivalent inanother protocol would then be transmitted to the MSC, providing the MSCwith the calling and called numbers, among other data. The MSC wouldthen engage in call-setup signaling, such as Integrated Services DigitalNetwork (ISDN) User Part (ISUP) signaling, over the SS7 network, to setup the call via a switching point that serves the called party. When thecalled party answers, the MSC may then connect the call. Similarly, whenthe MSC receives a request to connect a call to the mobile station, itwould typically cause the mobile station to be paged over the air, and,when the mobile station answers, connect the call. Both the paging andthe call connection would typically involve IS-2000 messaging.

With the widespread growth of voice-over-IP (VoIP) technology, theindustry has recently begun to introduce mobile stations—referred toherein as multi-mode devices—that are equipped to (i) operate in a CDMAmode, engaging in CDMA communications over a CDMA air interface with aRAN and (ii) operate in a Wi-Fi mode, engaging in VoIP communications inpart over Wi-Fi with an access point. The VoIP communications associatedwith Wi-Fi mode are typically set up using Session Initiation Protocol(SIP) messaging between the device and a signaling gateway having aninterface with a packet-based network and an interface with an SS7network. The signaling gateway translates between SIP messages and SS7messages to facilitate call processing over the SS7 network on behalf ofthe device.

For operation in these two modes, multi-mode devices typically includetwo substantially redundant, robust messaging modules: (1) a CDMAmessaging module, for engaging in CDMA signaling with a RAN (when inCDMA mode) and (2) a SIP messaging module, for engaging in SIP signalingwith a SIP/SS7 signaling gateway at least in part over Wi-Fi (when inWi-Fi mode). Each messaging module must be capable of handling callsetup, teardown, etc. Thus, where the CDMA messaging module would send,e.g., an IS-2000 origination message, the SIP messaging module may senda SIP INVITE message, and so on. Each of these messages would becomplete according to their respective protocols, and contain allnecessary data to carry out, in that example, a call-setup function.Development and maintenance of both of these messaging modules—as wellas translation and other support on the network side—requires asignificant investment of time, manpower, and other resources.

SUMMARY

Methods and systems are provided for encapsulating upper layers of CDMAsignaling between a multi-mode device and a signaling gateway. In oneaspect of the invention, an exemplary embodiment may take the form of amethod. In accordance with the method, an upper-layer portion of a CDMAsignaling message is generated. The upper-layer portion is encapsulatedin at least one packet-switched-protocol. The encapsulated upper-layerportion is transmitted via a Wi-Fi network and a packet-switched networkto a signaling gateway. The signaling gateway translates the upper-layerportion into an SS7 message and transmits the SS7 message over an SS7network.

These as well as other aspects and advantages will become apparent tothose of ordinary skill in the art by reading the following detaileddescription, with reference where appropriate to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary embodiments are described herein with reference to thefollowing drawings, wherein like numerals denote like entities.

FIG. 1 is a simplified block diagram of a communication system, inaccordance with exemplary embodiments;

FIG. 2 is a simplified block diagram of a multi-mode device, inaccordance with exemplary embodiments; and

FIG. 3 is a flowchart of a method, in accordance with exemplaryembodiments.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 1. Overview

Among other benefits and advantages, the present invention simplifiesmulti-mode devices by eliminating the robust SIP messaging moduledescribed above, such that the device will conduct all substantivesignaling using a CDMA (e.g., IS-2000) messaging module. When in CDMAmode, the device will engage in normal CDMA signaling with a RAN, asdescribed above. When in Wi-Fi mode, the device will not, however,engage in substantive SIP signaling as described above, but rather willencapsulate CDMA signaling messages in SIP (and/or another protocol),and transmit the encapsulated messages over a Wi-Fi network and apacket-switched network to a signaling gateway that will decapsulate theCDMA messages, translate them into SS7 messages, and transmit the SS7messages over an SS7 network.

Furthermore, when the device is in Wi-Fi mode, that same signalinggateway, and/or another, will receive SS7 messages over an SS7 network,translate the SS7 messages into CDMA (e.g., IS-2000) messages,encapsulate the CDMA messages in, e.g., SIP, and transmit theencapsulated messages, again perhaps over a packet-switched network anda Wi-Fi network, to the device. The device will then decapsulate andprocess the CDMA messages. Note that other packet-switched protocolscould be used instead of or in addition to SIP.

It should be noted as well that this encapsulation approach ispreferably employed with respect to some but not all CDMA messages. Someexamples of CDMA messages for which this approach would likely beemployed include registration messages, call-setup messages,call-teardown messages, handoff-related messages (i.e., maintenance ofthe device's CDMA active set, candidate set, etc., perhaps for purposesof vertical handoffs from Wi-Fi to CDMA), and teleservice messages(e.g., Short Message Service (SMS) messages, Wireless ApplicationProtocol (WAP) pushes, message-waiting indicators, etc.).

Some examples of CDMA messages for which this approach would preferablynot be employed include CDMA power-control messages, messages related toWalsh-code and/or PN-offset encoding and decoding, and others thatpertain not to call processing, but more to the air-interfacerelationship between the device and one or more CDMA base stations. Thisis not to say that the approach of the present invention could not beemployed with respect to these CDMA messages: only that, at present, inpreferred embodiments, the approach of the present invention is not usedwith respect to these messages.

Furthermore, the present invention does not contemplate using SIP toencapsulate CDMA messages in their entirety. In particular, CDMAmessages, like IP messages, include multiple stacked layers according todifferent protocols, and the present invention contemplates using SIP toencapsulate some but not all of those layers. Specifically, the presentinvention contemplates not encapsulating information at the Media AccessControl (MAC) and physical layers. These layers include large amounts ofdata that facilitate communication over CDMA air interfaces. Thisdata—such as Walsh-code and PN-offset encoding—is not needed whenexchanging SIP messages with a signaling gateway over Wi-Fi and apacket-switched network. Encapsulating these layers would be wasteful,resulting in much unnecessary processing.

According to the present invention, then, upper-layer portions ofcertain CDMA signaling messages would be encapsulated in SIP—and/oranother packet-switched protocol—and exchanged over Wi-Fi and apacket-switched network between a multi-mode device and a signalinggateway. In one exemplary embodiment, the upper-layer portions wouldinclude the layers between and including the presentation andcall-control layers. This is in contrast to the approach taken byUnlicensed Mobile Access (UMA), for example, according to which completeGlobal System for Mobile Communications (GSM) messages are encapsulatedin IP for transport over Wi-Fi and a packet-switched network to agateway. That is suited for GSM because GSM is atime-division-multiplexed protocol, and thus does not use the complexcoding at the physical layer employed in CDMA. As stated above,encapsulation and decapsulation of complete (i.e., Walsh-code andPN-offset encoded) CDMA messages would be wasteful.

Because the IS-2000 signaling messages and the SIP signaling messagesthat are used in current multi-mode-device implementations communicateessentially the same parameters (e.g., calling party, called party,Mobile Identification Number (MIN), Mobile Station Identification(MSID), Electronic Serial Number (ESN), Network Access Identifier (NAI),etc.), it is not necessary to have—and inefficient to maintain—bothmessaging modules on the device. Furthermore, in currentimplementations, a signaling gateway is needed to translate between SIPand SS7. The present invention eliminates the need for having andmaintaining that functionality on the network, as the network wouldalways be translating between CDMA (e.g., IS-2000) and SS7, rather thandoing that in addition to SIP/SS7 translations. And CDMA/SS7 (e.g.,IS-2000/SS7) translations are well established.

Thus, the present invention eliminates the need to separately developand maintain redundant functional modules, both on the multi-mode deviceand on the network. On the device, the robust SIP-messaging module iseliminated in favor of a simple SIP encapsulation engine (which wouldhandle both encapsulation and decapsulation). On the network side, theneed to translate between substantive SIP signaling messages and SS7messages is eliminated in favor of a combination of a similar SIPencapsulation engine and the existing and well-developed CDMA/SS7 (e.g.,IS-2000/SS7) translation functionality.

2. Exemplary Architecture

a. Exemplary Communication System

FIG. 1 is a simplified block diagram of a communication system, inaccordance with exemplary embodiments. It should be understood that thisand other arrangements described herein are set forth only as examples.Those skilled in the art will appreciate that other arrangements andelements (e.g., machines, interfaces, functions, orders, and groupingsof functions, etc.) can be used instead, and that some elements may beomitted altogether. Further, many of the elements described herein arefunctional entities that may be implemented as discrete or distributedcomponents or in conjunction with other components, and in any suitablecombination and location. Various functions described herein as beingperformed by one or more entities may be carried out by hardware,firmware, and/or software. Various functions may be carried out by aprocessor executing instructions stored in memory.

As shown in FIG. 1, a communication system 100 includes a multi-modedevice 102, a CDMA network 104, a Wi-Fi network 106, a PSTN 108, apacket-data network (PDN) 110, a media gateway 112, a signaling gateway114, and an SS7 network 116. And additional entities not depicted inFIG. 1 could be present as well. For example, there could be one or moreadditional multi-mode devices, other mobile stations, and/or otherdevices in communication with CDMA network 104, Wi-Fi network 106, PSTN108, and/or PDN 110. Also, there could be one or more devices and/ornetworks making up at least part of one or more of the communicationlinks. For example, there could be one or more routers, switches, orother devices or networks on the link between Wi-Fi network 106 and PDN110.

Multi-mode device 102 may be any mobile device capable of communicatingwith one or more CDMA networks, such as CDMA network 104, and with oneor more Wi-Fi networks, such as Wi-Fi network 106, and of carrying outthe multi-mode-device functions described herein. As such, multi-modedevice 102 may include a user interface, a wireless-communicationinterface, a processor, and data storage comprising instructionsexecutable by the processor for carrying out the multi-mode-devicefunctions described herein. The user interface may include buttons, atouch-screen, a microphone, and/or any other elements for receivinginputs, as well as a speaker, one or more displays, and/or any otherelements for communicating outputs.

Multi-mode device 102's wireless-communication interface may include oneor more chipsets and antennas, as well as any other hardware and/orsoftware, for enabling multi-mode device 102 to communicate with one ormore CDMA networks, such as CDMA network 104, and with one or more Wi-Finetworks, such as Wi-Fi network 106. This may involve two distinctwireless-communication interfaces, a single integratedwireless-communication interface capable of communication with bothtypes of networks, or perhaps some other arrangement.

FIG. 2 provides a functional look at multi-mode device 102. As shown inFIG. 2, multi-mode device 102 may include a CDMA messaging module 200, aCDMA communication module 202, an encapsulation engine 204, and a Wi-Ficommunication module 206. As stated herein, multi-mode device 102 mayhave a CDMA mode and a Wi-Fi mode. Furthermore, the functional entities200-206 may each comprise any combination of hardware and/or software.For example, CDMA messaging module 200 could be implemented as softwareinstructions and/or other data stored in memory and/or other datastorage, while CDMA communication module 202 may be implemented as acombination of software and hardware, perhaps including some componentsof the above-described wireless-communication interface.

In operation, CDMA messaging module 200 generates upper-layer portionsof CDMA signaling messages. For example, if the user initiates a call,CDMA messaging module 200 may responsively generate an upper-layerportion of an IS-2000 origination message. In general, the CDMAsignaling messages could be registration messages, call-setup messages,call-teardown messages, handoff-related messages, and/or any other typeof messages. And the upper-layer portions could include the layersbetween and including the presentation and call-control layers. Asanother example, the upper-layer portions could include the layers aboveand including the call-control layer. And other possibilities exist aswell.

When device 102 is in CDMA mode—communicating over a CDMA air interfacewith a CDMA network such as CDMA network 104, CDMA messaging module 200passes the upper-layer portions to CDMA communication module 202. When,however, device 102 is in Wi-Fi mode—communicating over a Wi-Fi airinterface with a Wi-Fi network such as Wi-Fi network 106, device 102instead passes those upper-layer portions to encapsulation engine 204.

And, when device 102 is in CDMA mode, CDMA messaging module 200 receivesupper-layer portions of CDMA signaling messages from CDMA communicationmodule 202. When device 102 is in Wi-Fi mode, however, CDMA messagingmodule 200 receives upper-layer portions of CDMA signaling messagesinstead from encapsulation engine 204. Either way, CDMA messaging module200 processes the received upper-layer portions, which may involveexamining the contents of the upper-layer portions, or perhaps passingthose upper-layer portions to some other functional entity.

In a corresponding manner, when device 102 is in CDMA mode, CDMAcommunication module 202 receives upper-layer portions of CDMA signalingmessages from CDMA messaging module 200. CDMA communication module 202then adds lower-layer portions (such as MAC and physical-layer portions,including PN-offset and Walsh-code encoding) to the upper-layer portionsto provide complete CDMA signaling messages, and transmits the completeCDMA signaling messages over an air interface to CDMA network 104. CDMAcommunication module 202 also receives complete CDMA signaling messagesfrom CDMA network 104, removes lower-layer (e.g., MAC and physical)portions to provide upper-layer portions of CDMA signaling messages, andpasses the upper-layer portions to CDMA messaging module 200.

When, however, device 102 is in Wi-Fi mode, encapsulation engine 204receives upper-layer portions of CDMA signaling messages from CDMAmessaging module 200, encapsulates the upper-layer portions in at leastone packet-switched protocol (e.g., SIP and/or IP), and passes theencapsulated upper-layer portions to Wi-Fi communication module 206.Encapsulation engine 204 also receives encapsulated upper-layer portionsof CDMA signaling messages from Wi-Fi communication module 206,decapsulates them, and passes them to CDMA messaging module 200.

Also when device 102 is in Wi-Fi mode, Wi-Fi communication module 206receives encapsulated upper-layer portions of CDMA signaling messagesfrom encapsulation engine 204, and transmits them over a Wi-Fi airinterface to Wi-Fi network 106 for delivery to signaling gateway 114. Inso doing, Wi-Fi communication module 206 may format the encapsulatedupper-layer portions for transmission over Wi-Fi. Wi-Fi communicationmodule 206 also receives encapsulated upper-layer portions of CDMAsignaling messages over a Wi-Fi air interface from Wi-Fi network 106,and passes them to encapsulation engine 204.

With respect to voice traffic, both modes of multi-mode device 102 mayinvolve using a codec known as the Enhanced Variable Rate Codec (EVRC)for encoding audible voice input in a digitized format for transmission,and for decoding voice data received in that digitized format to produceaudible voice output. In CDMA mode, the EVRC traffic could be exchangedover the CDMA air interface with the RAN using Walsh-code and PN-offsetencoding. In Wi-Fi mode, the EVRC traffic could be exchanged usingRTP/IP, in part over Wi-Fi and in part over other elements and networksmaking up a packet-switched communication path with a gateway or otherendpoint. It should be understood, however, that codecs other than EVRCand transport protocols other than RTP could be used.

Returning the reader's attention to FIG. 1, CDMA network 104 may includea number of devices that cooperate to communicate with multi-mode device102 over an air interface according to a CDMA standard such as IS-95 orIS-2000, and to thereby provide multi-mode device 102 with the abilityto communicate over PSTN 108 and PDN 110. As such, CDMA network 104 maybe communicatively connected to at least PSTN 108, PDN 110, and SS7network 116 (for setting up calls over PSTN 108). CDMA network 104 mayinclude one or more base stations with which device 102 communicatesover the air interface. These base stations may be connected to andcontrolled by one or more base station controllers (BSCs). The BSCs, inturn, may be connected to one or more mobile station controllers (MSCs),which are switching elements that may communicate over SS7 network 116and provide access to PSTN 108. The BSCs may also be connected to one ormore packet data serving nodes (PDSNs), which provide packet-dataconnectivity to PDN 110.

Wi-Fi network 106 may include a number of devices that cooperate tocommunicate with multi-mode device 102 over an air interface accordingto a Wi-Fi standard such as IEEE 802.11, and to thereby providemulti-mode device 102 with the ability to communicate over PDN 110.Wi-Fi network 106 may include at least one access point with whichmulti-mode device 102 communicates over the Wi-Fi air interface. Theaccess point may in turn be connected with a network access device suchas a cable modem, DSL modem, network access server, or other datacommunication device, which in turn provides connectivity with PDN 110.

PSTN 108 may be the well-known telephony network known as the publicswitched telephone network, and may be communicatively coupled with atleast CDMA network 104, media gateway 112, and SS7 network 116. PDN 110may be communicatively coupled with at least CDMA network 104, Wi-Finetwork 106, media gateway 112, and signaling gateway 114, and mayinclude one or more wide area networks, one or more local area networks,one or more public networks such as the Internet, one or more privatenetworks, one or more wired networks, one or more wireless networks,and/or one or more networks of any other variety. Devices incommunication with PDN 110 may exchange data using a packet-switchedprotocol such as IP, and may be identified by an address such as an IPaddress.

Media gateway 112 may be any networking device arranged to provide alink between PSTN 108 and PDN 110, and to carry out the media-gatewayfunctions described herein. As such, media gateway 112 may include aprocessor and data storage comprising instructions executable by theprocessor to carry out the media-gateway functions described herein.Media gateway 112 may also include an interface with PSTN 108, and aninterface with PDN 110, and may (i) receive circuit-switchedcommunications from PSTN 108, convert those communications to apacket-switched format, and transmit the converted communications overPDN 110 and (ii) receive packet-switched communications from PDN 110,convert those communications to a circuit-switched format, and transmitthe converted communications over PSTN 108.

Signaling gateway 114 may be any networking device arranged to provide alink between PDN 110 and SS7 network 116, and generally to carry out thesignaling-gateway functions described herein. As such, signaling gateway114 may include a processor and data storage comprising instructionsexecutable by the processor to carry out the signaling-gateway functionsdescribed herein. Signaling gateway 114 may also include an interfacefor communicating over PDN 110, and an interface for communicating overSS7 network 116.

Signaling gateway 114 may receive, from multi-mode device 102 over Wi-Finetwork 106 and PDN 110, upper-layer portions of CDMA signaling messagesencapsulated in at least one packet-switched protocol. Signaling gateway114 then decapsulates the upper-layer portions, translates them into SS7messages, and transmits the SS7 messages over SS7 network 116. Signalinggateway 114 may also function to receive SS7 messages over SS7 network116, translate them into upper-layer portions of CDMA signalingmessages, encapsulate the upper-layer portions in at least onepacket-switched protocol, and transmit the encapsulated upper-layerportions to device 102 over PDN 110 and Wi-Fi network 106. Note thatsignaling gateway 114 may translate between SS7 messages and upper-layerportions of CDMA signaling messages with reference to a conversiontable, other conversion logic, and/or in any other manner.

Note that the CDMA signaling messages could be IS-2000 messages, andcould include registration, call-setup, call-teardown, handoff, and/orany other types of messages. And the upper-layer portions of thesemessages could consist of the layers between and including thepresentation and call-control layers, the layers above and including thecall-control layer, and/or any otherwise-defined upper-layer portions.Furthermore, as examples, the packet-switched protocol could be SIPand/or IP, and the SS7 messages could be ISUP messages.

SS7 network 116 may be the well-known SS7 network commonly used toperform call-processing functions on behalf of telephony endpoints. Assuch, SS7 network 116 may include signal transfer points (STPs), signalcontrol points (SCPs), and/or any other elements now known or laterdeveloped for use in signaling networks. SS7 network may becommunicatively connected to at least CDMA network 104, PSTN 108, andsignaling gateway 114.

3. Exemplary Operation

FIG. 3 depicts a flowchart of an exemplary method, in accordance with anexemplary embodiment. As shown in FIG. 3, a method 300 begins at step302, when multi-mode device 102 generates an upper-layer portion of aCDMA signaling message, perhaps by making use of CDMA messaging module200. As stated herein, the CDMA signaling message could be an IS-2000message, such as a registration message, a call-setup message, acall-teardown message, and/or a handoff message. Furthermore, also asstated herein, the upper-layer portion could consist of the layersbetween and including the presentation and call-control layers, orperhaps the layers above and including the call-control layer.

At step 304, multi-mode device 102 encapsulates the upper-layer portiongenerated in step 302 in at least one packet-switched-protocol. Thus,CDMA messaging module 200 could—since, in this example, device 102 isoperating in Wi-Fi mode—pass the generated upper-layer portion toencapsulation engine 204, which could then encapsulate the upper-layerportion in SIP, IP, and/or any other packet-switched protocol. As oneexample, step 304 could involve generating a SIP MESSAGE (or another SIPmethod) for transmission to signaling gateway 114.

At step 306, multi-mode device 102 transmits the encapsulatedupper-layer portion via Wi-Fi network 106 and PDN 110 to signalinggateway 114, which then translates the upper-layer portion into an SS7message, and transmits that SS7 message over SS7 network 116. As such,whatever call-processing function device 102 intended can be carried outover SS7 network 116.

Note that multi-mode device 102 may also receive encapsulatedupper-layer portions of CDMA signaling messages from signaling gateway114, via PDN 110 and Wi-Fi network 106. This may occur as a result ofsignaling gateway 114 receiving SS7 messages over SS7 network 116,converting them into the upper-layer portions of CDMA signalingmessages, encapsulating the upper-layer portions, and then sending theencapsulated upper-layer portions over PDN 110 and Wi-Fi network 106 todevice 102. Multi-mode device 102 may then decapsulate the receivedencapsulated upper-layer portions, perhaps by making use ofencapsulation engine 204, and then process the received upper-layerportions, perhaps by making use of CDMA messaging module 200, and/or oneor more other functional modules.

4. Conclusion

Various exemplary embodiments have been described above. Those skilledin the art will understand, however, that changes and modifications maybe made to those examples without departing from the scope of theclaims.

1. A multi-mode device having a Code Division Multiple Access (CDMA)mode and a Wi-Fi mode, and comprising a CDMA messaging module, a CDMAcommunication module, an encapsulation engine, and a Wi-Fi communicationmodule, wherein: the CDMA messaging module (i) (a) generates upper-layerportions of CDMA signaling messages and (b) passes the upper-layerportions to the CDMA communication module when the device is in CDMAmode and instead to the encapsulation engine when the device is in Wi-Fimode, and (ii) (a) receives upper-layer portions of CDMA signalingmessages from the CDMA communication module when the device is in CDMAmode and instead from the encapsulation engine when the device is inWi-Fi mode and (b) processes the upper-layer portions; when the deviceis in CDMA mode, the CDMA communication module (i) (a) receivesupper-layer portions of CDMA signaling messages from the CDMA messagingmodule, (b) adds lower-layer portions to the upper-layer portions toprovide complete CDMA signaling messages, and (c) transmits the completeCDMA signaling messages over a CDMA air interface to a CDMA network and(ii) (a) receives complete CDMA signaling messages over a CDMA airinterface from a CDMA network, (b) removes lower-layer portions from thecomplete CDMA signaling messages to provide upper-layer portions of CDMAsignaling messages, and (c) passes the upper-layer portions to the CDMAmessaging module; when the device is in the Wi-Fi mode, theencapsulation engine (i) (a) receives upper-layer portions of CDMAsignaling messages from the CDMA messaging module, (b) encapsulates theupper-layer portions in at least one packet-switched protocol, and (c)passes the encapsulated upper-layer portions to the Wi-Fi communicationmodule and (ii) (a) receives encapsulated upper-layer portions of CDMAsignaling messages from the Wi-Fi communication module, (b) decapsulatesthe upper-layer portions, and (c) passes the upper-layer portions to theCDMA messaging module; and when the device is in Wi-Fi mode, the Wi-Ficommunication module (i) (a) receives encapsulated upper-layer portionsof CDMA signaling messages from the encapsulation engine and (b)transmits the encapsulated upper-layer portions over a Wi-Fi airinterface to a Wi-Fi network for delivery to a signaling gateway and(ii) (a) receives encapsulated upper-layer portions of CDMA signalingmessages over a Wi-Fi air interface from a Wi-Fi network and (b) passesthe encapsulated upper-layer portions to the encapsulation engine. 2.The multi-mode device of claim 1, wherein the CDMA mode is an IS-2000mode, the CDMA messaging module is an IS-2000 messaging module, the CDMAcommunication module is an IS-2000 communication module, the CDMAsignaling messages are IS-2000 signaling messages, the CDMA airinterface is an IS-2000 air interface, and the CDMA network is anIS-2000 network.
 3. The multi-mode device of claim 1, wherein the Wi-Fimode is an Institute of Electronics and Electrical Engineers (IEEE)802.11 mode, the Wi-Fi communication module is an IEEE 802.11communication module, the Wi-Fi air interface is an IEEE 802.11 airinterface, and the Wi-Fi network is an IEEE 802.11 network.
 4. Themulti-mode device of claim 1, wherein the at least onepacket-switched-protocol comprises at least one of the SessionInitiation Protocol (SIP) and the Internet Protocol (IP).
 5. Themulti-mode device of claim 1, wherein the upper-layer portions of CDMAsignaling messages consist of (i) a plurality of layers between andincluding a presentation layer and a call-control layer or (ii) aplurality of layers above and including a call-control layer.
 6. Themulti-mode device of claim 1, wherein the CDMA signaling messagescomprise at least one of a registration message, a call-setup message, acall-teardown message, a handoff message, and a teleservice message.